1广东省农业科学院作物研究所 / 广东省农作物遗传改良重点实验室,广州 510640;2 四川农业大学玉米研究所,成都 611130
1Institute of Crops,Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of Crop Genetic Improvement, Guangzhou 510640;2 Maize Research Institute of Sichuan Agricultural University,Chengdu 611130
Guangdong Provincial Key Research and Development Program, 2018B020202008，
Using maize haploid embryogenic callus as genetic transformation receptor and combining with chemical doubling method, homozygous individuals whenever hosting a transgenic element might be obtained in a short time. This study attempted to obtain haploid callus from maize using diploid embryogenic callus induction method, followed by analyzing the detection rate of haploid callus, browning rate and mortality after different subculture times, as well as diploid callus and haploid callus growth rate and other important indicators. The haploid callus was treated with 0.005%-0.03% colchicine, and the mortality rate of haploid callus, powder dispersal rate after adult, ratio of large anther (strong pollen vigor), seed setting rate and plant ratio of more than 5 seeds were analyzed. The results showed that induction of haploid embryogenic callus was applicable using the improved method of diploid callus induction. The detection rate of haploid callus is 4.2%, similar to the induction rate of 18-599(red) by MT-1 lines. Both the browning rate and mortality of haploid callus were significantly higher than diploid callusof the same time of subculture, and both the browning rate and mortality rate of haploid callus reached the highest level after three inductions. With callus diameter as reference, the growth rate of haploid callus was lower than t diploid,. , which could be used as an key reference indicator to distinguishhaploid and diploid callus in the early growth period. After being treated with colchicine of different concentrationsfor different period of time, the pollinating rate, rate of large anther, seed setting rate and ratio of plants with more than 5 seeds of haploid callus increased as the concentration increases and the time prolongs, and survival rate and small anther (of poor or no viability), on the other hand, drops as the concentration increases and the time prolongs.. The results showed that colchicine treatment could enhance the pollinating rate and seed setting rate of maize callus in adult plants where higher seed setting rate was dependent on higher rate of large anther.. Collectively, this paper includes analysis of multiple factors in the process of callus induction and doubling of maize haploid. And screened out 0.01% colchicine treatment for 12h and 0.02% colchicine treatment for 3h) as better modesfor doubling of maize haploid callus.